A Photoredox-Induced Stereoselective Dearomative Radical (4+2)-Cyclization/1,4-Addition Cascade for the Synthesis of Highly Functionalized Hexahydro-1H-carbazoles

Dirk Alpers; Malte Gallhof; Julian Witt; Frank Hoffmann; Malte Brasholz

doi:10.1002/anie.201610974

A Photoredox-Induced Stereoselective Dearomative Radical (4+2)-Cyclization/1,4-Addition Cascade for the Synthesis of Highly Functionalized Hexahydro-1H-carbazoles

Angew Chem Int Ed Engl. 2017 Jan 24;56(5):1402-1406. doi: 10.1002/anie.201610974. Epub 2017 Jan 9.

Authors

Dirk Alpers¹, Malte Gallhof¹, Julian Witt¹, Frank Hoffmann², Malte Brasholz¹

Affiliations

¹ Department of Chemistry-Institute of Organic Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146, Hamburg, Germany.
² Department of Chemistry-Institute of Inorganic Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146, Hamburg, Germany.

PMID: 28067443
DOI: 10.1002/anie.201610974

Abstract

A stereoselective synthesis of functionalized hexahydrocarbazoles was developed based on an unprecedented photoredox-induced dearomative radical (4+2)-cyclization/1,4-addition cascade between 3-(2-iodoethyl)indoles and acceptor-substituted alkenes. The title reaction simultaneously generates three C-C bonds and one C-H bond, along with three contiguous stereogenic centers. The hexahydro-1H-carbazole products are highly valuable intermediates for the synthesis of novel antibiotics, as well as unnatural ring homologues of polycyclic indoline alkaloids.

Keywords: carbazoles; cascade reactions; indolines; photocatalysis; radicals.

Publication types

Research Support, Non-U.S. Gov't